Originally Posted by flyingeph12

You can change the date of your ORD-NRT-ICN flights without paying a fee and without affecting the other segments in your itinerary. You can push out those flights up to a year from the date you originally ticketed the award.

Canceling the ORD-ICN in theory should be possible since it appears to be a separate award, but since all of your awards are in one record, it may cause some issues. I think a date change is a safer bet if you plan on using it at a later date.